Safety device for mobile work platforms

ABSTRACT

A land vehicle assembly is provided with a platform for an operator workspace. A control panel is supported upon the platform in electrical communication with the land vehicle. A caution switch is supported upon the platform in electrical communication with the control panel to provide a signal to the control panel indicative of a caution event. A cable is connected to the caution switch to extend across the control panel. The cable is spaced apart from the control panel so that a predetermined force upon the flexible member actuates the caution switch without significantly obstructing the control panel. A manual force upon the flexible member expands the operator workspace. The control panel is programmed to control a mobile operation of the land vehicle, and discontinue the mobile operation of the land vehicle in response to receipt of the caution event signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/808,257 filed Nov. 9, 2017, now U.S. Pat. No. 10,549,975 B2, which,in turn, claims the benefit of U.S. provisional application Ser. No.62/421,537 filed Nov. 14, 2016, the disclosures of which are herebyincorporated in their entirety by reference herein.

TECHNICAL FIELD

Various embodiments relate to safety devices for mobile work platforms.

BACKGROUND

Hao et al. U.S. Patent Application Publication Number US 2013/0233645A1, and Cummings et al. U.S. Patent Application Publication Number US2015/0008073 A1 disclose safety devices for mobile work platforms.

SUMMARY

According to at least one embodiment, a mobile work platform assembly isprovided with a platform adapted to be mounted to a vehicle. Theplatform is sized to receive an operator thereupon. A control panel issupported upon the platform. A caution switch is supported upon theplatform. The caution switch is in electrical communication with thecontrol panel to provide a signal to the control panel indicative of acaution event. A flexible member is connected to the caution switch toextend across the control panel and is spaced apart from the controlpanel so that a predetermined force upon the flexible member actuatesthe caution switch.

According to at least another embodiment, a land vehicle assembly isprovided with a land vehicle. A mobile work platform assembly isprovided with a platform adapted to be mounted to a vehicle. Theplatform is sized to receive an operator thereupon. A control panel issupported upon the platform. A caution switch is supported upon theplatform. The caution switch is in electrical communication with thecontrol panel to provide a signal to the control panel indicative of acaution event. A flexible member is connected to the caution switch toextend across the control panel and is spaced apart from the controlpanel so that a predetermined force upon the flexible member actuatesthe caution switch. The land vehicle supports the platform and is inelectrical communication with the control panel. The control panel isprogrammed to control at least one mobile operation of the land vehicle,and discontinue the at least one mobile operation of the land vehicle inresponse to receipt of the caution event signal.

According to at least another embodiment, a method for selecting acaution mode of a mobile work platform provides a mobile work platformwith a control panel. A caution switch is provided in communication withthe control panel. A flexible member extends across the control paneland is connected to the caution switch. A mobile function of the mobilework platform is discontinued in response to receipt of a caution signalfrom the caution switch.

According to at least another embodiment, a mobile work platformassembly provides a platform adapted to be mounted to a vehicle. Theplatform is sized to receive an operator thereupon. A control panel issupported upon the platform. A caution switch is supported upon theplatform in electrical communication with the control panel to provide asignal to the control panel indicative of a caution event. A barriermember is removably connected to the caution switch and the platform toextend across the control panel. The barrier member is spaced apart fromthe control panel so that a predetermined force upon the barrier memberdisconnects the barrier member from the platform and actuates thecaution switch.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a mobile work platform assemblyaccording to an embodiment;

FIG. 2 is an enlarged front perspective view of a control panel of themobile work platform assembly of FIG. 1;

FIG. 3 is a circuit diagram of the control panel of the mobile workplatform assembly of FIG. 1;

FIG. 4 is a front perspective view of mobile work platform assemblyaccording to another embodiment;

FIG. 5 is an enlarged front perspective view of a connector assembly ofthe mobile work platform assembly of FIG. 4;

FIG. 6 is an enlarged side perspective view of the connector assembly ofFIG. 5; and

FIG. 7 is an enlarged front perspective view of another connectorassembly of the mobile work platform assembly of FIG. 4.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

FIG. 1 illustrates a mobile work platform assembly referenced generallyby numeral 10. The mobile work platform assembly 10 is adapted to bemounted to a land vehicle, such as an aerial lift, as is known in theart, and will be described further in a subsequent embodiment. Themobile work platform assembly 10 includes a platform 12 sized to receivean operator upon the platform 12. A frame assembly 14 is provided uponthe platform 12. The frame assembly 14 provides a frame of guard railsthat extend around a perimeter of the platform 12 to contain an operatorwithin the frame assembly 14. A door 16 is provided upon the frameassembly 14 to permit operator ingress to, and egress from, the frameassembly 14.

Referring now to FIGS. 1 and 2, a control panel assembly 18 is providedupon the mobile work platform assembly 10. The control panel assembly 18includes hand controls 20 and a foot switch 22. The foot switch 22 islabeled FS in the circuit diagram of FIG. 3. Referring back to FIGS. 1and 2, the control panel assembly 18 is in communication with theassociated land vehicle to control movement of the vehicle and the workplatform assembly 10 relative to an underlying support surface. Forexample, the control panel assembly 18 may control transportation of theland vehicle upon the underlying support surface. The control panelassembly 18 may also control a lift mechanism for adjusting an elevationof the work platform assembly 10. The control panel assembly 18 permitsthe operator to move the work platform assembly 10 adjacent to anotherwise unreachable work region. The work platform assembly 10provides a remote platform 12 for the operator to conduct work upon theassociated work region.

The work platform assembly 10 includes a caution or safety device 24 tominimize involuntary operation of the control panel assembly 18,referred to as an operator protection system 24. During a workoperation, an operator may inadvertently contact the control panelassembly 18. The safety device 24 minimizes involuntary operation of thecontrol panel assembly 18 to minimize involuntary operation of the landvehicle and lift so that actuation of the safety device 24 disruptscontrol of the land vehicle and the lift.

Additionally, an operator may operate the control panel assembly 18 tomove the work platform assembly 10 while overlooking or unaware of anobstacle. The operator protection system 24 protects the operator frombeing trapped between an external structure and the control panelassembly 18 by stopping the movement of the work platform assembly 10once the caution device 24 is activated. This operator protection system24 is a robust system that is unobtrusive, does not block the operator'sview of the control panel assembly 18, and provides additional workspaceupon the platform 12, once the operator protection system 24 isinitiated.

The operator protection system 24 includes a pair of brackets 26, 28that extend into from the frame assembly 14 into a workspace within theperimeter of the frame assembly 14. The operator protection system 24includes a trigger cable 30 with a proximal end 32 (FIG. 1) that isconnected to the right bracket 28. With reference now to FIG. 2, amagnet 34 is connected to a distal end of the cable 30. The magnet 34affixes within a receptacle 36 on the left bracket 26. An inductive orproximity sensor 38 is provided in the receptacle 36 adjacent to themounting surface of the magnet 34 to detect the presence of the magnet34. Although, the pair of brackets 26, 28 are provided on the frame 14,the trigger cable 30 may be connected to any support structure on thework platform assembly 10.

The cable 30 is attached at the distal end with the magnet 34 to aferrous connection in the receptacle 36 of the left bracket 26. Theproximal end 32 is attached to the right bracket 28 and pretensionedslightly so as to give some movement to the cable 30, yet dislodge themagnet 34 from the receptacle 36 once additional tension is applied tothe cable 30. Referring now to FIGS. 1-3, the position of the magnet 34is detected by the proximity switch 38, which is labeled LS for limitswitch in the circuit diagram of FIG. 3. The limit switch LS, 38 ismonitored by a processor or electronic control unit (ECU) in FIG. 3.When the trigger cable 30 is pushed upon, the cable 30 translates themagnet 34 away from a ferrous attachment in the receptacle 36. Removalof the magnet 34 activates the proximity switch 38.

In response to the activation of the proximity switch 38, the ECUinitiates a caution or safety mode. In the caution mode, the ECUterminates movement of the work platform assembly 10 by stopping allmotion of the land vehicle and the lift. The ECU also initiates an audioand visual alarm by initiating a horn (FIG. 3) and strobe light emittingdiodes (LEDs) (also FIG. 3).

The prior art has offered machine controls that are mounted on apivoting or movable mount that trips a switch once displaced from normaloperating position. This prior art system requires the operator to bepressed into the controls to stop movement of the machine. This priorart system does not allow any additional space for the operator afterthe switch has been tripped. This prior art system may also createopportunities for the pivot/movable mount to become contaminated bydebris or corrosion causing malfunctions and requiring maintenance andrepair.

The prior art has also offered a pressure sensitive bar or switchmounted in front of the control panel. This prior art system requiresthe operator to be pressed into the pressure bar to stop movement of themachine. This prior art system does not provide additional space for theoperator after the switch is tripped. The pressure sensitive bar is alsowithin the workspace and may be accidentally tripped thereby creatingnuisance mobility stoppages.

The prior art has also offered a pressure sensitive bar or switchmounted a distance above a leading edge of the controls on a breakawaymount. This prior art system requires the operator to be pressed intothe pressure bar to stop movement of the machine. Due to the nature ofthe breakaway system, this prior art system is vulnerable to breakage ina construction environment. In addition, this prior art system createsan obstruction when viewing the operator controls.

Some prior art systems require an operator to replace parts that requiretools for the replacement, in order to reset the system.

The operator protection system 24 provides simplicity over the prior artby providing a device that utilizes no moving switch contacts and allowsthe proximity switch 38 to be concealed in a protected location withinthe receptacle 36. The operator protector system 24 also providesenhanced visibility over the prior art. By utilizing the cable 30 toactuate the switch 38, visual obstructions of the control panel assembly18 are minimized. Due to the visibility improvement, the operatorprotection system 24 allows the switch 38 to be located in an optimalposition for actuation when needed, and creates additional workspace forthe operator between the cable 30 and the control panel assembly 18 oncethe cable 30 has been disconnected from the receptacle 36. Although thecable 30 is illustrated and described, any suitable flexible member iscontemplated, such as a chain, rope, or the like. Although one magnet 34and sensor 38 is illustrated and described, any number of magnetconnections with sensors may be employed. The operator protection system24 is easily resettable, without requiring tools or replacement parts.For example, when the operator trips the protection system 24, but isnot in danger, the operator can simply grab ahold of the magnet 34 andreinsert it into the receptacle 36, and the mobile work platformassembly 10 returns to normal operation.

FIG. 4 illustrates a land vehicle 50 according to an embodiment. Theland vehicle 50 includes a lift arm 52, which supports a mobile workplatform assembly 54 according to another embodiment. The mobile workplatform assembly 54 is illustrated in FIGS. 4-7. The mobile workplatform assembly 54 includes a platform 56 (FIG. 6), a frame assembly58, and a control panel assembly 60.

A pair of brackets 62, 64 is mounted to the frame assembly 58. Anoperator protection system 66 is mounted to the pair of brackets 62, 64.With reference to FIGS. 4-6 a socket 68 is supported upon the rightbracket 64. Referring specifically to FIG. 6, the socket 68 includes abore 70 and a pair or spring-loaded ball bearings 72. Referring again toFIGS. 4-6, the operator protection system 66 includes a cable 74. Adistal end of the cable 74 is provided with a threaded stud 76 forconnection to a plug 78. The plug 78 is sized to be received in thesocket 68. A groove 80 is formed in the plug 78 to receive the ballbearings 72 to retain the plug 78 in the socket 68. According to oneembodiment, a limit switch is provided in the socket 68 to detect thepresence of the plug 78.

Referring now to FIGS. 4 and 7, a limit switch 82 is provided on theleft bracket 62. A proximal end of the cable 74 is connected to thelimit switch 82. The cable 74 is tensioned so that the limit switch isfreely maintained in a neutral position. At the neutral position, thecontrol panel assembly 60 permits operation of the land vehicle 50 andlift arm 52. The tension of the cable 74 can be adjusted by the positionof the plug 78 upon the threaded stud 76. If the cable 74 is pushed orpulled, the limit switch 82 is actuated, thereby informing the controlpanel assembly 60 of a caution event, whereby the control panel assembly60 discontinues operation of the land vehicle 50 and lift arm 52 whileproviding a light and sound alarm. If the displacement of the cable 74is more than a stroke of the limit switch 82, the plug 78 is removedfrom the socket 68, thereby dropping the cable 74 and providingadditional workspace for the operator. The plug 78 and cable 74 havesufficient weight to keep the switch 82 in the caution position untilreinstalled into the socket 68. Although one plug 78 and socket 68connection is illustrated and described, both ends of the cable 74 maybe connected with plug 78 and socket 68 connections, with limit switchesin one or both sockets 68. Although a cable 74 is illustrated anddescribed, any barrier member for manual disconnection from the frameassembly 58 may be employed. The operator protection system 66 is easilyresettable, without requiring tools or replacement parts. For example,when the operator trips the protection system 66, but is not in danger,the operator can simply grab ahold of the plug 78 and reinsert it intothe socket 70, and the mobile work platform assembly 10 returns tonormal operation.

While various embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. A mobile work platform assembly comprising: a platform adapted to be mounted to a vehicle, sized to receive an operator thereupon; a control panel supported upon the platform; a caution switch supported upon the platform; a flexible member associated with the caution switch to extend across the control panel and spaced apart from the control panel so that a predetermined force upon the flexible member actuates the caution switch; and a magnet connected to one of an end of the flexible member and the platform to attach the flexible member to the platform.
 2. The mobile work platform assembly of claim 1 wherein the platform provides an operator workspace; and wherein a manual force upon the flexible member expands the operator workspace.
 3. The mobile work platform assembly of claim 1 wherein the caution switch cooperates with the magnet to detect a presence and removal of the magnet from the platform.
 4. The mobile work platform assembly of claim 1 wherein the magnet is connected to the end of the flexible member, and the platform is formed from a ferrous material to attach the magnet to the platform.
 5. The mobile work platform assembly of claim 4 wherein a receptacle is formed into the platform, sized to receive the magnet.
 6. The mobile work platform assembly of claim 5 wherein the caution switch comprises an inductive sensor oriented in the receptacle adjacent to a mounting surface of the magnet to detect a presence and removal of the magnet.
 7. The mobile work platform assembly of claim 1 wherein the flexible member comprises a cable to minimize visual obstruction of the control panel.
 8. The mobile work platform assembly of claim 7 wherein the cable is pretensioned to permit limited flexibility of the cable upon receipt of a force that is less than the predetermined force.
 9. A land vehicle assembly comprising: a land vehicle; and a mobile work platform assembly according to claim 1; and wherein the land vehicle supports the platform and is in electrical communication with the control panel, wherein the control panel is programmed to: control at least one mobile operation of the land vehicle, and discontinue the at least one mobile operation of the land vehicle in response to receipt of a caution event signal from the caution switch.
 10. The mobile work platform assembly of claim 1 further comprising an alarm supported upon the platform in electrical communication with the control panel, wherein the control panel is programmed to initiate the alarm in response to receipt of a caution event signal from the caution switch.
 11. A mobile work platform assembly comprising: a platform adapted to be mounted to a vehicle, sized to receive an operator thereupon; a control panel supported upon the platform; a caution switch supported upon the platform in electrical communication with the control panel; a flexible barrier member associated with the caution switch, the flexible barrier member extending across the control panel and spaced apart from the control panel so that a predetermined force upon the flexible barrier member actuates the caution switch to indicate a caution event; and a magnet connected to one of an end of the flexible barrier member and the platform to attach the flexible barrier member to the platform.
 12. A mobile work platform assembly comprising: a platform adapted to be mounted to a vehicle, sized to receive an operator thereupon; a control panel supported upon the platform; a caution switch supported upon the platform; and a barrier member removably connected to the caution switch and the platform to extend across the control panel and spaced apart from the control panel so that a predetermined force upon the barrier member disconnects the barrier member from the platform and actuates the caution switch; further comprising a magnet connected to one of an end of the barrier member and the platform to attach the barrier member to the platform. 